Modified polyphenylene ether, process for preparing the same and thermoplastic resin composition comprising the same

ABSTRACT

A modified polyphenylene ether comprising repeating units of the formula (1): ##STR1## wherein R 1  and R 2  are, independently from each other, a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms and having a number average polymerization degree of 20 to 12,000, in which 0.02/X to 1/X of methyl groups at the 2- and/or 6-positions of phenylene group are substituted by an aminomethyl group wherein X is a number average polymerization degree, a process for preparing the same, and a thermoplastic resin composition containing (A) 1 to 75% by weight of the above modified polyphenylene ether and (B) 99 to 25% by weight of a liquid crystalline polyester. 
     Since this modified polyphenylene ether includes a highly reactive primary amine on the polymer side chain, it is preferably used in a wide range as a component of various compositions or polymer alloys. The thermoplastic resin composition is excellent in heat resistance, mechanical properties and appearance and gloss of a molded article.

This application is a continuation of PCT/JP93/01050 filed Dec. 7, 1994.

FIELD OF THE INVENTION

The present invention relates to a novel modified polyphenylene ethercomprising repeating units in which a methyl group at 2- and/or6-position of a phenylene group in the polyphenylene ether issubstituted with an aminomethyl group, and a process for preparing thesame.

The present invention also relates to a novel thermo-plastic resincomposition which can be used, for example, in the production of amolded article by injection molding or extrusion molding.

PRIOR ART

In general, a polyphenylene ether is a resin having various goodproperties such as heat resistance, hot water resistance, dimensionalstability and mechanical and electrical properties. On the other hand,has some drawbacks such as its molding property is not good because ofits high melt viscosity, its chemical resistance is not good and itsimpact resistance is low. To improve such drawbacks of the polyphenyleneether, it has been alloyed with another resin or modified.

For example, Japanese Patent KOKAI Publication No. 897/1977 discloses aprocess for modifying a polyphenylene ether using an aliphatic secondaryamine as one component of a polymerization catalyst. Japanese PatentKOKAI Publication No. 68024/1992 discloses a process for preparing apolyphenylene ether having a terminal secondary amino group comprisingreacting a polyfunctional isocyanate with the polyphenylene ether, andJapanese Patent KOKAI Publication No. 313523/1989 discloses a processfor preparing a polyphenylene ether having a terminal functional groupcontaining a secondary or tertiary amino group. Japanese Patent KOKAIPublication No. 297428/1989 discloses a polyphenylene ether copolymerhaving an alkyl-substituted tertiary amine on a methylene group at the2-position. Japanese Patent KOKAI Publication No. 234421/1989 relates toa polyphenylene ether copolymer having a partly aryl-substitutedtertiary amine on a side methylene group at the 2-position.

Japanese Patent KOKAI Publication No. 503464/1988 relates to apolyphenylene ether having a polyalkylene dicarboxylate. Japanese PatentKOKAI Publication No. 37365/1990 discloses a polyphenylene ether havinga primary amino group on a propylene group in a side chain.

Different from a crystalline polymer such as polyethylene terephthalateor polybutylene terephthalate, a liquid crystalline polyester does notsuffer from tangling of molecules in a molten state since the moleculesare stiff, forms a polydomain having a crystal state, and molecularchains are highly orientated in a flow direction at a low shear. Then,the liquid crystalline polyester is generally called a thermotropicliquid crystal polymer. Because of such specific behaviors, its meltflowability is excellent and it can easily provide a thin-wall moldedarticle having a thickness of about 0.2 to 0.5 mm, and the moldedarticle advantageously has a high strength and high stiffness, while thedrawbacks are that its anisotropy is large and its weld strength is verylow.

In addition, the liquid crystalline polyester is expensive, which isanother problem. In the market, it is highly desired to provide a liquidcrystalline polyester resin composition which maintains good heatresistance and mechanical properties of the liquid crystallinepolyester, has improved weld strength and is cheap.

To improve the molding processability and strength of the liquidcrystalline polyester by the addition of an amorphous polymer to theliquid crystalline polyester, Japanese Patent KOKAI Publication No.115357/1981 describes the improvement of melt processability of theliquid crystalline polyester by the addition of a polymer such as apolyphenylene ether to the liquid crystalline polyester.

Further, Japanese Patent KOKAI Publication No. 97555/1990 describes theblending of various polyallylene oxides in the liquid crystallinepolyester to improve the soldering heat resistance.

However, some of the modified polyphenylene ethers prepared by the abovedescribed processes are easily decomposed in the processing to generatebad odor or decrease the physical properties, some of them haveinsufficient reactivities of the functional groups which are introducedin the molecular chains, or some of them are expensive.

There has not been obtained an economical modified polyphenylene ethercomprising repeating units in which a methyl group in the polyphenyleneether is substituted with a highly reactive aminomethyl group, and suchmodified polyphenylene ether has been highly desired by the market.

A composition comprising the liquid crystalline polyester having a highmolding temperature and an amorphous polymer having a lower moldingtemperature than that such as the polyphenylene ether may have improvedmelt processability, but the molded article has poor appearance due tothermal decomposition of the compounded resins in the molding step. Inaddition, such composition has insufficient mechanical properties andheat resistance.

It may be effective to improve compatibility by blending a modifiedpolyphenylene ether in which a functional group is introduced in theliquid crystalline polyester. However, such blending increases the cost,and in some cases, a monomer having the functional group or oligomersremain in the composition and decrease the physical properties of thecomposition, which causes some problems.

Therefore, it is highly desired by the market to provide a thermoplasticresin composition which contains a highly reactive functional group suchas a primary amine in a molecule, comprises a cheap modifiedpolyphenylene ether and a liquid crystalline polyester, and hasexcellent physical properties.

SUMMARY OF THE INVENTION

As a result of an extensive study to solve the above problems, thepresent invention has been completed.

Accordingly, the present invention provides a modified polyphenyleneether, a process for preparing the same, and a liquid crystallinepolyester resin composition as described below:

(I) A modified polyphenylene ether comprising repeating units of theformula (1): ##STR2## wherein R₁ and R₂ are, independently from eachother, a hydrogen atom or a hydrocarbon group having 1 to 20 carbonatoms and having a number average polymerization degree of 20 to 12,000,in which 0.02/X to 1/X of methyl groups at the 2- and/or 6-positions ofphenylene group are substituted by an aminomethyl group wherein X is anumber average polymerization degree.

(II) A process for preparing a modified polyphenylene ether comprisingpolymerizing a nucleus-substituted phenol of the formula (2): ##STR3##wherein R₃, R₄ and R₅ are, independently from each other, a hydrogen ora hydrocarbon group having 1 to 20 carbon atoms using an oxidativecoupling catalyst in the presence of an amine of the formula (3):##STR4## wherein Q₁ and Q₂ are, independently from each other, ahydrogen, an alkyl group having 1 to 24 carbon atoms or an aralkyl grouphaving 7 to 24 carbon atom, provided that Q₁ and Q₂ are notsimultaneously hydrogen atoms, or Q₁ and Q₂ are both alkylene groups andforms a ring, in an amount of 0.001 to 0.2 mole per one mole of thenucleus-substituted phenol, and melt kneading the resultingpolyphenylene ether.

(III) A liquid crystalline polyester resin composition comprising (A) 1to 75% by weight of a modified polyphenylene ether comprising repeatingunits of the formula (1) and having a number average polymerizationdegree of 20 to 12,000, in which 0.02/X to 1/X of methyl groups at the2- and/or 6-positions of phenylene group are substituted by aminomethylgroup wherein X is a number average polymerization degree, and (B) 99 to25% by weight of a liquid crystalline polyester.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plain view of a specimen used in measurement of weldstrength.

FIG. 2A and 2B show graphs of heat weight changes of polyphenyleneethers in the nitrogen atmosphere.

FIG. 3 is a two-dimensional HMQC NMR spectrum of the polyphenylene ether(R-1).

FIG. 4 is a two-dimensional HMQC NMR spectrum of the polyphenylene ether(A-1).

DETAILED DESCRIPTION OF THE INVENTION

First, the modified polyphenylene ether of the present invention will beexplained.

The present invention relates to a novel modified polyphenylene ethercomprising repeating units in which the methyl groups at the 2- and/or6-positions of the phenylene groups are substituted with the aminomethylgroups (--CH₂ NH₂). The repeating units substituted with the aminomethylgroups may be terminal repeating units, or may be present atintermediate positions of the backbone. In particular, the polyphenyleneether comprising the aminometyl-substituted repeating units as theterminal units is preferred since it can be easily prepared.

The modified polyphenylene ether of the present invention ischaracterized in that 0.02/X to 1/X, preferably 0.05/X to 1/X of themethyl groups at the 2- and/or 6-positions of the phenylene group aresubstituted by the aminomethyl group wherein X is a number averagepolymerization degree.

When the number of the aminomethyl groups is less than 0.02/X of themethyl groups at the 2- and/or 6-positions of the phenylene groups, theheat resistance or the mechanical properties are not sufficientlyimproved when the modified polyphenylene ether is used as a component ofa polymer alloy.

The modified polyphenylene ether of the present invention comprises 20to 1200, preferably 30 to 1000 repeating units of the formula (1) on thenumber average. When the number of the repeating units of the formula(1) is outside this range, the processability of the resin may bedeteriorated, or the mechanical properties may be insufficient.

As a polymer alloy component, the polyphenylene ether comprising theunsubstituted repeating units of the formula (1) has an insufficientreactivity with other resins, while the modified polyphenylene ethercomprising the repeating units in which the methyl groups at the 2-and/or 6-positions of the phenylene groups of the polyphenylene etherare substituted by the aminomethyl groups has a good reactivity and ispreferable as the polymer alloy component.

The process for preparing the modified polyphenylene ether of thepresent invention will be explained.

One of the preferred processes for preparing the modified polyphenyleneether of the present invention comprises polymerizing anucleus-substituted phenol of the above formula (2) using an oxidativecoupling catalyst in the presence of an amine of the above formula (3)in an amount of 0.001 to 0.2 mole per one mole of thenucleus-substituted phenol, and melt kneading the resultingpolyphenylene ether.

This process is explained more in detail. In the process forpolymerizing the nucleus-substituted phenol of the formula (2) in thepresence of the oxidative coupling catalyst, the polymerization iscarried out in the presence of the amine of the formula (3). The amineis present in an amount of 0.001 to 0.2 mole, preferably 0.005 to 0.05mole per one mole of the nucleus-substituted phenol. When the amount ofthe amine is less than 0.001 mole per one mole of thenucleus-substituted phenol, any polyphenylene ether having goodproperties is not obtained. When the amount exceeds 0.2 mole, anypolyphenylene ether having a practical molecular weight cannot beobtained.

As described above, the polyphenylene ether having the amine on the sidechains can be obtained.

Herein, the nuclei-substituted phenol is a compound of the formula (2),and can be used independently, or as a mixture of two or more of thephenols.

Preferred examples of the nucleus-substituted phenol are2,6-dimethylphenol, 2,3,6-trimethylphenol and the like. Among them,2,6-dimethylphenol is particularly preferred.

Specific examples of the amine of the formula (3) are primary aminessuch as n-propylamine, isopropylamine, n-butylamine, isobutylamine,sec.-butylamine, n-hexylamine, n-octylamine, 2-ethylhexylamine,cyclohexylamine, laurylamine, benzylamine, etc.; and secondary aminessuch as diethylamine, di-n-propylamine, di-nbutylamine, diisobutylamine,di-n-octylamine, piperidine, 2-pipecoline, etc. A polyamine which isregarded as having the amine of the formula as a repeating unit isequivalent to the amine of the formula (3). Examples of such polyaminear ethylenediamine, piperazine, 1,3-dipiperidylpropane, and the like.

Specifically, it is preferred to use the amine of the formula (3) and aknown catalyst system comprising a copper compound, a mangnese compoundor a cobalt compound and a ligand selected from bases.

There are exemplified a process comprising oxidation coupling the phenolmonomer and oxygen in the presence of a catalyst comprising a manganesesalt, a basic reaction medium and a secondary amine as disclosed inJapanese Patent KOKAI Publication No. 79993/1978; and a process foroxidation polymerizing the nucleus-substituted phenol with anoxygen-containing gas in an organic solvent in the presence of acatalyst comprising one or more divalent manganese salts, at least onebase compound selected from the group consisting of an hydroxidealkoxide or phenoxide of a metal of the IA group of the Periodic Tableand a hydroxide or oxide of a metal of the IIA group, an alkanol amineand an amine as disclosed in Japanese Patent KOKAI Publication No.54424/1988.

By the above process, the polyphenylene ether comprising the repeatingunits in which the methyl groups at the 2- and/or 6-positions of thephenylene group are changed to the group of the formula (4): ##STR5##wherein Q₁ and Q₂ are the same as defined above can be obtained.

The above repeating unit to which the secondary or tertiary amine isbonded may be the terminal unit of the polyphenylene ether, or may bepresent in the intermediate of the backbone. In particular, thepolyphenylene ether comprising the such repeating units as the terminalunits is preferred since it can be easily prepared.

Then, the polyphenylene ether in which the methyl groups at the 2-and/or 6-positions of the phenylene groups are substituted by thesecondary or tertiary amine is melt kneaded to obtain the modifiedpolyphenylene ether of the present invention.

The raw material polyphenylene ether is preferably charged in a kneadingapparatus under a nitrogen atmosphere.

The melt kneading is carried out at a cylinder temperature of 200° to300° C., preferably 230° to 280° C. When the cylinder temperature islower than 200° C., the molding processability of the raw materialpolyphenylene ether is not good, while when the cylinder temperature ishigher than 300° C., the polyphenylene ether may be unpreferablydecomposed or gelled. The melt kneading is preferably carried out whileventing.

For melt kneading, conventionally used kneading apparatuses such assingle or twin screw extruders, various types of kneader and the likecan preferably used.

The polyphenylene ether may be melt kneaded by adding a radicalinitiator during kneading. Alternatively, the radical initiator can beadded to the polyphenylene ether and then melt kneaded. Preferablyusable radical initiators include cumene hydroperoxide, tert.-butylhydroperoxide, dimethyl-2,5-bis(hydroperoxy)hexane,1,3-bis(tert.-butylperoxyisopropyl)benzene, tert.-butyl peroxide,2,6-di-tert.-butyl-4-methylphenol, and the like.

The thermoplastic resin composition of the present invention will beexplained.

The component (A) of the thermoplastic resin composition of the presentinvention is the above described modified polyphenylene ether.

To the modified polyphenylene ether as the component (A) of thethermoplastic resin composition of the present invention, unmodifiedpolyphenylene ether, styrene-grafted polyphenylene ether, polystyreneand the like can be added, if desired.

Preferably, the modified polyphenylene ether as the component (A) of thethermoplastic resin composition of the present invention and the rawmaterial polyphenylene ether therefor have a reduced viscosity η_(sp) /c(measured at 25° C. with a chloroform solution of 0.5 g/dl) of 0.30 to0.65 dl/g. When η_(sp) /c is lower than 0.30 dl/g, the heat resistanceof the composition is severely deteriorated, while when η_(sp) /cexceeds 0.65 dl/g, the moldability of the composition is deteriorated.

The liquid crystalline polyester as the component (B) of thethermoplastic resin composition of the present invention is thepolyester which is called as the thermotropic liquid crystallinepolymer.

Specific examples of such polymer are

(1) a polymer comprising an aromatic dicarboxylic acid, an aromatic dioland an aromatic hydroxycarboxylic acid;

(2) a polymer comprising different aromatic hydroxycarboxylic acids;

(3) a polymer comprising an aromatic dicarboxylic acid and anucleus-substituted aromatic diol; or

(4) a polymer prepared by reacting an aromatic hydroxycarboxylic acidwith a polyester such as polyethylene terephthalate.

Such polymer forms an anisotropic melt at a temperature not higher than400° C.

In place of the aromatic dicarboxylic acid, aromatic diol and aromaticdihydroxycarboxylic acid, their ester-forming derivatives may be used.

As the repeating units of the liquid crystalline polyester, thefollowing repeating units can be exemplified. Repeating units derivedfrom the aromatic carboxylic acids: ##STR6## Repeating units derivedfrom the aromatic diols: ##STR7## Repeating units derived from thearomatic hydroxydicarboxylic acids: ##STR8##

The particularly preferred liquid crystalline in view of the balanceamong the heat resistance, the mechanical properties and theprocessability is one comprising the repeating units of the formula:##STR9## more concretely, the polyester comprising each of thecombinations (I) to (V) of the repeating units: ##STR10##

The liquid crystalline polyesters (I), (II), (III) and (IV) aredisclosed in Japanese Patent Publication Nos. 47870/1972, 3888/1988,3891/1988 and 18016/1981, respectively.

In the present invention, when a ratio of the components (A) and (B) arein the specific range, the desired thermoplastic resin composition canbe obtained. Amounts of the components (A) and (B) in the presentinvention are preferably from 1 to 75% by weight and 99 to 25% byweight, respectively.

When the amount of the component (A) is less than 1% by weight, there isno merit in the cost, while when it exceeds 75% by weight, thecomposition may have insufficient heat resistance or strength.

In the thermoplastic resin composition of the present invention,preferably, the component (A) forms a dispersed phase, while thecomponent (B) forms a continuous phase. In such case, the composition isexcellent in chemical resistance, heat resistance, mechanicalproperties, and the like.

If desired, the thermoplastic resin composition of the present inventionmay contain an inorganic filler.

As the inorganic filler, there are exemplified calcium carbonate, talc,clay, silica, magnesium carbonate, barium sulfate, titanium oxide,alumina, gypsum, glass fiber, carbon fiber, alumina fiber, aluminumborate whisker, potassium titanate fiber, and the like.

If necessary, to the thermoplastic resin composition of the presentinvention, additional various additives such as an antioxidant, a heatstabilizer, a light stabilizer, a flame retardant, a lubricant, anantistatic agent, an organic or inorganic colorant, a rust preventive, across-linking agent, a foaming agent, a fluorescent, a surface smoother,a surface gloss improver, a releasing improver (e.g. a fluororesin),etc. may be added during the production step or the subsequentprocessing step of the composition.

As the production method of the thermoplastic resin composition of thepresent invention, there are exemplified a method comprising meltkneading the polyphenylene ether in the kneader to prepare beforehandthe modified polyphenylene ether of the component (A), compounding theliquid crystalline polyester of the component (B) and kneading them, anda method comprising dissolving each of the above prepared modifiedpolyphenylene ether of the component (A) and the liquid crystallinepolyester of the component (B) in respective solvents, mixing twosolutions, and evaporating off the solvents or pouring the mixture in asolvent in which the resin components are not dissolved to precipitatethe resin composition.

Alternatively, the polyphenylene ether is charged through a first feedopening of the extruder and melt kneaded in a part of the extruderbetween the first feed opening and a second feed opening to prepare themodified polyphenylene ether of the component (A). Thereafter, theliquid crystalline polyester of the component (B) is charged through thesecond feed opening, and the modified polyphenylene ether and the liquidcrystalline polyester are melt kneaded to obtain the resin composition.

In any case, it is possible to confirm that the component (A)constituting the obtained resin composition is the modifiedpolyphenylene ether having the primary amine by, for example, extractingeither the modified polyphenylene ether or the polyphenylene ether fromthe composition with a solvent, reprecipitating the polymer andquantitatively analyzing the amine species in the extracted component bythe potentiometric titration.

While a reason why the thermoplastic resin composition of the presentinvention has excellent physical properties has not been clarified, itmay be assumed as follows:

Since the polyphenylene ether comprising only the repeating units (1)has no reactive functional group, it has an insufficient reactivity withthe liquid crystalline polyester, so that the composition comprisingsuch polyphenylene ether and the liquid crystalline polyester may nothave good physical properties.

On the other hand, since the modified polyphenylene ether which issubstituted with the aminomethyl groups contains the highly reactiveprimary amine, the reaction may take place between the modifiedpolyphenylene ether and the liquid crystalline polyester, and as theresults, the composition may have the excellent physical properties. de

EXAMPLES

The present invention will be explained by the following Examples, whichdo not limit the present invention by any way. A number averagemolecular weight, an amount of the amine and NMR are measured asfollows:

Number Average Molecular Weight

A number average molecular weight is measured by the gel permeationchromatography (hereinafter referred to as "GPC") according to aconventional manner.

Measurement of amounts of amines in the raw material

polyphenylene ether and the modified polyphenylene ether

-Nitrogen content in the whole amine

About one gram of a sample is weighed and dissolved in chloroform (50cc). After the addition of acetic acid (5 cc), the solution is analyzedby potentiometric titration using a potentiometric titration apparatusAT-310 (manufactured by Kyoto Electronics, Co., Ltd.) (a glass-calomelelectrode, a titrant: 0.1M perchloric acid (acetic acid solution)), andthe nitrogen content in the whole amine is calculated according to thefollowing equation:

N_(T) =0.0014×A×C₁ ×100/S

NT: Nitrogen content in the whole amine (%)

A: Titer (cc)

S: Sample amount (g)

C₁ : Concentration of the perchloric acid solution (mole/I)

-Nitrogen content in the tertiary amine

About one gram of a sample is weighed and dissolved in chloroform (50cc). Acetic anhydride (5 cc) was added to the solution, the solution iskept standing, and then acetic acid (5 cc) is added. Thereafter, thepotentiometric titration is carried out in the same way as in thetitration of the nitrogen content in the whole amine, and the nitrogencontent in the tertiary amine is calculated according to the followingequation:

N₃ =0.0014×B×C₂ ×100/S

N₃ : Nitrogen content in the whole amine (%)

B: Titer (cc)

S: Sample amount (g)

C₂ : Concentration of the perchloric acid solution (mole/I)

-Nitrogen content in the secondary amine

About one gram of a sample is weighed and dissolved in chloroform (50cc). Salicyl aldehyde (5 cc) was added to the solution and the solutionis kept standing. Thereafter, the potentiometric titration is carriedout in the same way as in the titration of the nitrogen content in thewhole amine except that a 0.1 mole/I solution of hydrochloric acid in2-propanol is used as a titrant. First, the nitrogen content N₂,3 in thesample (secondary amine+tertiary amine) is calculated according to thefollowing equation:

N₂,3 =0.014×C×D'100/S

C: Concentration of hydrochloric acid for titration (mole/I)

D: Titer (cc)

S: Sample amount (g)

Thereafter, the nitrogen content N₂ (%) of the secondary amine containedin the sample is calculated according to the following equation:

N₂ =N₂,3 -N₃

-Nitrogen content in the primary amine

The nitrogen content N₁ (%) of the primary amine contained in the sampleis calculated according to the following equation:

N₁ =N_(T) -N₂ -N₃

NMR Measurement

Using a spectrometer AMX 600 (manufactured by Bulker), the NMRmeasurement is carried out at 600.14 MHz of the resonance frequency for¹ H, and 150.92 MHz of the resonance frequency for ¹³ C.

A sample is dissolved in CDCI₃ and the measuring temperature is 40° C.

Chemical shifts are calculated with the peak of CHCI₃ being 7.24 ppm inthe case of ¹ H-NMR and with the peak of CDCI₃ being 77.1 ppm in thecase of ¹³ C-NMR.

The peaks of R-1 were assigned according to those described inMacromolecules, 23, 1318-1329 (1990).

Measurement of physical properties of molded article

Physical properties are measured with a molded article which is producedby kneading a composition using the PCM-30 type twin screw extruder(manufactured by Ikegai Tekko Co., Ltd.) at a cylinder temperature of300° to 340° C. and injection molding the composition using the PS 40 E5ASE type injection molding apparatus (manufactured by Nissei Jushi KogyoCo., Ltd.) at a barrel temperature of 300° to 340° C. and a moldtemperature of 110° to 130° C.

<Tensile strength and temperature of deflection under

load (TDUL)>

An ASTM No. 4 dumbbell and a specimen for TDUL measurement (127 mmlong×2.7 mm wide×6.4 mm thick) are molded and the tensile strength andthe TDUL (under load of 18.6 kg) are measured according to ASTM D638 andASTM D648, respectively.

<Flexural strength>

The flexural strength is measured with a specimen (6.4 mm thick)according to ASTM D790 (weld part strength and non-weld part strength).

From a composition of the present invention, a specimen shown in FIG. 1is molded, which has a thickness of 3 mm, an outer size of 64 mm and aninner size of 38 mm. From the specimen, a hatched part 2 (64×13 mm)including the weld line 1 is cut out, and its flexural strength ismeasured at a span distance of 40 mm and a bending rate of 2 mm/min.

From a specimen having the same shape as above, a non-weld part (64×13mm)is cut out, and its flexural strength is measured in the same way.

<Appearance of molded article>

The appearance of the molded article is evaluated according to thefollowing criteria:

O: Appearance is good and no color change is found.

X: Color change is found on the molded article surface.

<Morphological observation of molded article>

An injection molded article is sliced with a microtome and etched withcarbon tetrachloride, and the etched specimen is observed by a scanningelectron microscope and classified as follows:

A: The polyphenylene ether parts (modified PPE and unmodified PPE) formdispersed phases, while the liquid crystalline polyester part forms acontinuous phase.

B: The polyphenylene ether part forms a continuous phase, while theliquid crystalline parts form dispersed phases.

Reference Example 1

In a jacketed 10 liter autoclave equipped with a stirrer, a thermometer,a condenser and an air inlet tube which reached the bottom of theautoclave, xylene (3420 g), methanol (1366 g), 2,6-dimethylphenol (1222g, 10.02 moles) and sodium hydroxide (24 g) were charged to form ahomogeneous solution. Then, the solution was added to a solution ofdiethanolamine (33.8 g), di-n-butylamine (27.7 g, 0.233 molecorresponding to 0.0233 mole per one mole of 2,6-dimethylphenol) andmanganese chloride tetrahydrate (0.99 g) dissolved in methanol (100 g).

While vigorously stirring the content, an air was bubbled through thecontent at 5 liter/min. The reaction temperature and pressure weremaintained at 35° C. and 9 kg/cm², respectively. After 7 hours from thestart of air bubbling, the air supply was stopped, and the reactionmixture was poured in a mixture of acetic acid (66 g) and methanol (4900g). The resulting slurry was filtrated under reduced pressure to isolatea polyphenylene ether in a wet state.

After the isolated polyphenylene ether was washed with methanol (7200g), it was dried at 150° C. under reduced pressure overnight to obtainthe dried polyphenylene ether (1160 g).

The polyphenylene ether had a number average molecular weight of 6000and a number average polymerization degree of 50. This polyphenyleneether will be referred to as "R-1."

The nitrogen contents of various amines in R-1 are shown in Table 1.From these contents, it is seen that 0.43% of the methyl groups at the2- and 6-positions of the polyphenylene ether were substituted by thetertiary dibutylamino groups.

Example 1

The polyphenylene ether R-1 (100 parts by weight), a radicalpolymerization initiator (Sunperox T0, a trade name of Sanken Kako Co.,Ltd.) (0.2 part by weight), an antioxidant (Irganox 1330, a trade name)(0.3 part by weight) and 2,6-di-tert.-butyl-4-methylphenol (0.2 part byweight) were mixed in a Henschel mixer, and kneaded using a twin screwextruder PCM-30 (manufactured by Ikegai Tekko Co., Ltd.) by charging itin a hopper which had been kept under a nitrogen atmosphere, at acylinder temperature of 273° C. at a screw rotation of 80 rpm whileventing. The obtained pellets were dissolved in chloroform andreprecipitated in methanol and dried. This modified polyphenylene etherhad a number average molecular weight of 6800 and a number averagepolymerization degree of 56.7. This modified polyphenylene ether will bereferred to as "A-1."

The nitrogen contents of various amines in A-1 are shown in Table 1.Comparing with the raw material polyphenylene ether, it is seen that themodified polyphenylene having the greatly decreased amount of tertiaryamine and the greatly increased amount of primary amine was obtained.

                  TABLE 1                                                         ______________________________________                                        Results of quantitative analysis of nitrogen in the polyphenylene             ether and modified polyphenylene ether                                                 Nitrogen contents (%)                                                Sample     N.sub.T                                                                              N.sub.1     N.sub.2                                                                             N.sub.3                                   ______________________________________                                        R-1        0.10   <0.01       <0.01 0.10                                      A-1        0.09   0.07        <0.01 0.02                                      ______________________________________                                    

From the above results, it is seen that 0.30% of the methyl group at the2- and 6-positions of the polyphenylene ether were replaced by theaminomethylene groups.

To compare the heat stability of R-1 and A-1, thermogravimetric analysisthereof was carried out using TGA-50 (manufactured by ShimadzuCorporation) at a heating rate of 10° C./min. To compensate thedifference of surface areas between R-1 and A-1, A-1 was finely ground(42 mesh) till no dependency on the particle size was found in theweight-temperature curve and used in the analysis. FIG. 2 shows theresults of thermogravimetric analysis measured in the nitrogenatmosphere. The graphs (1) and (2) in FIG. 2 show the results of R-1 andA-2, respectively.

In the Figure, the main decomposition temperature was obtained from anintersection between the base line and a tangent at a steepestinclination point of the base line shift, and the decomposition startingtemperature was a temperature at which the weight decreased by 2%.

As seen from FIG. 2, the weight loss of R-1 started around 350° C., andthe decomposition starting temperature as low as 405° C., whilesubstantially no weight loss of A-1 was found up to around 400° C., andthe decomposition starting temperature was 438° C. which was at least30° C. higher than that of R-1. While R-1 had the main decompositiontemperature of 435° C., A-1 had the main decomposition temperature of450° C. These results show that the modified polyphenylene ether had theimproved heat stability.

The two dimensional HMQC NMR spectra of R-1 and A-1 are shown in FIGS. 3and 4, respectively.

In FIG. 3, the ordinate and the abscissa represent the chemical shiftsof ¹³ C and ¹ H, respectively.

In this spectrum, since decoupling of ¹³ C was not effected duringmeasurement, one signal was observed as two peaks split in the ¹ H axisdirection.

The ¹³ C-NMR chemical shift of the signal was given at the peakposition, and the 1H-NMR chemical shift was given as the middle pointbetween the two split peak positions, which is shown by the arrow.

In FIG. 4, the ordinate and the abscissa represent the chemical shiftsof ¹³ 3C and ¹ H, respectively.

In this spectrum, since decoupling of ¹³ C was not effected duringmeasurement, one signal was observed as two peaks split in the ¹ H axisdirection.

The ¹³ C-NMR chemical shift of the signal was given at the peakposition, and the 1H-NMR chemical shift was given as the middle pointbetween the two split peak positions, which is shown by the arrow.

The assignments of the major peaks are as follows:

In the two dimensional HMQC NMR spectrum of R-1, the signal having thechemical shifts of ¹³ C:58.1 ppm and ¹ H:3.62 ppm is assigned to thecarbon and hydrogen atoms, respectively of the methylene group at the 2-or 6-position of the phenylene group in the polyphenylene ether to whichthe dibutylamine is bonded according to Macromolecules, 23, 1318 (1990).The intensity of this signal greatly decreased in A-1, while the newsignal having the chemical shifts of ¹³ C:36.3 ppm and ¹ H:3.89 ppmappears. It is known that the chemical shift of a carbon atom of amethylene group in a benzyl group to which a primary amine is bonded is39.4 ppm according to Phytochem., 18, 1547 (1979), and that the chemicalshift of a hydrogen atom of the methylene group in the benzyl group towhich the primary amine is bonded is 3.9 ppm according to AldrichLibrary of NMR Spectra, II, 1066 (1983). Accordingly, the signal havingthe chemical shifts of ¹³ C:36.3 ppm and ¹ H:3.89 ppm is assigned to thecarbon atom and hydrogen atom, respectively of the methylene group atthe 2- or 6-position of the phenylene group of polyphenylene ether towhich the primary amine is bonded.

These results coincide with the above results of titration analysis ofthe amino groups.

Reference Example 2

in a polymerization tank equipped with a comb-form agitation blade,p-acetoxybenzoic acid (10.8 kg, 60 moles), terephthalic acid (2.49 kg,15 moles), isophthalic acid (0.83 kg, 5 moles) and4,4'-diacetoxydiphenyl (5.45 kg, 20.2 moles) were charged, heated up to330° C. and polymerized at the same temperature for one hour whilestirring in the nitrogen atmosphere. The polymerization was proceededunder vigorous stirring with removing by-produced acetic acid.Thereafter, the reaction system was gradually cooled, and the reactionmixture was removed from the tank at 200° C. The reaction mixture wasground by a hammer mill (manufactured by Hosokawa Micron Co., Ltd.) toparticles of 2.5 mm or less. Then, the ground mixture was treated in arotary kiln at 280° C. in the nitrogen atmosphere for 3 hours to obtaina particulate whole aromatic polyester having a flow temperature of 324°C. and comprising the following repeating units. This liquid crystallinepolyester will be referred to as "B-1". The repeating units of theliquid crystalline polyester B-1 were as follows: ##STR11##

Examples 2 and 3 and Comparative Examples 1 and 2

The components having the composition of Table 2 were mixed with astabilizer and kneaded, and then the properties were measured. Theresults are shown in Table 2.

Examples 4 and 5 and Comparative Examples 3 and 4

The components having the composition of Table 3 were mixed with astabilizer and kneaded, and then the properties were measured. Theresults are shown in Table 3.

                                      TABLE 2                                     __________________________________________________________________________                         Physical properties                                                                  Tensile                                                                            Flexural                                                                           Flexural                                Example                                                                            Composition (wt. %)                                                                           TDUL   strength                                                                           strength                                                                           modulus                                 No.  Component (A)                                                                         Component (B)                                                                         (18.6 kg, °C.)                                                                (kg/cm.sup.2)                                                                      (kg/cm.sup.2)                                                                      (kg/cm.sup.2)                                                                      Morphology                                                                           Appearance                  __________________________________________________________________________    2    A-1, 30 B-1, 70 231    1320 1140 62000                                                                              A      ◯               C.1  R-1, 30 B-1, 70 215    850  960  44000                                                                              A      X                           3    A-1, 50 B-1, 50 198    860  840  41000                                                                              A      ◯               C.2  R-1, 50 B-1, 50 188    440  450  32000                                                                              A      X                           __________________________________________________________________________

                                      TABLE 3                                     __________________________________________________________________________                    Physical properties                                                                      Flexural test                                                                            Weld test                               Composition (wt. %)                                                                           TDUL  Tensile                                                                            Flexural                                                                            Flexural                                                                           Weld  Nol-weld                          Example                                                                            Compo-                                                                              Compo-                                                                             (18.6 kg,                                                                           strength                                                                           strength                                                                            modulus                                                                            part  part                              No.  nent(A)                                                                             nent (B)                                                                           (°C.)                                                                        (kg/cm.sup.2)                                                                      (kg/cm.sup.2)                                                                       (kg/cm.sup.2)                                                                      (kg/cm.sup.2)                                                                       (kg/cm.sup.2)                                                                      Morphology                                                                           Appearance            __________________________________________________________________________    4    A-1, 10                                                                             B-1, 90                                                                            254   1470 1100  64000                                                                              320   800  A      ◯         C.3  R-1, 10                                                                             B-1, 90                                                                            233   1100 980   52000                                                                              220   640  A      X                     5    A-1, 40                                                                             B-1, 60                                                                            206   950  920   47000                                                                              290   590  A      ◯         C.4  R-1, 40                                                                             B-1, 60                                                                            202   680  690   40000                                                                              220   430  A      X                     __________________________________________________________________________

The composition of Example 2 was refluxed in chloroform for 72 hours,and the amine species in the modified PPE which is soluble in chloroformwere quantitatively analyzed. Hereinafter, the modified PPE will bereferred to as "A-2".

The composition of Comparative Example 1 was treated in the same manneras above, and the amine species in the PPE were quantitatively analyzed.This PPE will be referred to as "R-2".

The results of the quantitative analysis of the amine species are shownin Table 4.

                  TABLE 4                                                         ______________________________________                                        Results of quantitative analysis of nitrogen in the polyphenylene             ether and modified polyphenylene ether                                                 Nitrogen contents (%)                                                Sample     N.sub.T                                                                              N.sub.1     N.sub.2                                                                             N.sub.3                                   ______________________________________                                        R-2        0.10   <0.01       <0.01 0.10                                      A-2        0.07   0.05        <0.01 0.02                                      ______________________________________                                    

It is seen that the thermoplastic resin composition of the presentinvention is excellent in heat resistance, various properties such asmechanical properties and melt processability, and has good appearanceof the molded article. In addition it is an economical resincomposition.

EFFECTS OF THE INVENTION

Since the modified polyphenylene ether of the present invention includesa highly reactive primary amine on the polymer side chain, it ispreferably used in a wide range as a component of various compositionsor polymer alloys. Further, it is cheap.

The thermoplastic resin composition of the present invention isexcellent in heat resistance, mechanical properties and appearance andgloss of the molded article. By making use of such characteristics, itis used in the production of a molded article, a sheet, a tube, a film,fibers, a laminate, a coating material and the like, by injectionmolding and extrusion molding.

What is claimed is:
 1. A modified polyphenylene ether comprisingrepeating units of the formula (1): ##STR12## wherein R₁ and R₂ are,independently from each other, a hydrogen atom or a hydrocarbon grouphaving 1 to 20 carbon atoms and having a number average polymerizationdegree of 20 to 12,000, in which 0.02/X to 1/X of methyl groups at the2- and/or 6-positions of phenylene group are substituted by anaminomethyl group wherein X is a number average polymerization degree.2. The modified polyphenylene ether according to claim 1, wherein bothR₁ and R₂ of the repeating unit (1) are hydrogen atoms.
 3. A process forpreparing a modified polyphenylene ether comprising polymerizing anucleus-substituted phenol of the formula (2): ##STR13## wherein R₃, R₄and R₅ are, independently from each other, a hydrogen or a hydrocarbongroup having 1 to 20 carbon atoms using an oxidative coupling catalystin the presence of an amine of the formula (3): ##STR14## wherein Q₁ andQ₂ are, independently from each other, a hydrogen, an alkyl group having1 to 24 carbon atoms or an aralkyl group having 7 to 24 carbon atoms,provided that Q₁ and Q₂ are not simultaneously hydrogen atoms, or Q₁ andQ₂ are both alkylene groups and form a ring, in an amount of 0.001 to0.2 mole per one mole of the nucleus-substituted phenol, and meltkneading the resulting polyphenylene ether in a nitrogen atmosphere at atemperature of 200° to 300° C. while venting.
 4. The process accordingto claim 3, wherein the melt kneading is carried out in a nitrogenatmosphere at a temperature of 200° to 300° C. while venting.
 5. Theprocess according to claim 3 or 4, wherein the melt kneading is carriedout in the presence of a radical initiator.
 6. The process according toclaim 5, wherein said radical initiator is at least one compoundselected from the group consisting of cumene hydroperoxide, tert.-butylhydroperoxide, dimethyl-2,5-bis(hydroperoxy)hexane,1,3-bis(tert.-butylperoxyisopropyl)benzene, tert.-butyl peroxide and2,6-di-tert.-butyl-4-methylphenol.
 7. The process according to claim 3wherein said amine of the formula (3) is at least one amine selectedfrom the group consisting of n-propylamine, isopropylamine,n-butylamine, isobutylamine, sec.-butylamine, n-hexylamine,n-octylamine, 2-ethylhexylamine, cyclohexylamine, laurylamine,benzylamine, diethylamine, di-n-propylamine, di-n-butylamine,diisobutylamine, di-n-octylamine, piperidine and 2-pipecoline.
 8. Theprocess according to claim 3, wherein said nucleus-substituted phenol is2,6-dimethylphenol and/or 2,3,6-trimethylphenol.
 9. A liquid crystallinepolyester resin composition comprising (A) 1 to 75% by weight of amodified polyphenylene ether comprising repeating units of the formula(1): ##STR15## wherein R₁ and R₂ are, independently from each other, ahydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms andhaving a number average polymerization degree of 20 to 12,000, in which0.02/X to 1/X of methyl groups at the 2- and/or 6-positions of phenylenegroup are substituted by aminomethyl group wherein X is a number averagepolymerization degree, and(B) 99 to 25% by weight of a liquidcrystalline polyester.
 10. The thermoplastic resin composition accordingto claim 9, wherein the modified polyphenylene ether as the component(A) has a reduced viscosity η_(sp) /c (measured at 25° C. with achloroform solution of 0.5 g/dl) of 0.30 to 0.65 dl/g.
 11. Thethermoplastic resin composition according to claim 9, wherein saidcomponent (A) forms a dispersed phase, and said component (B) forms acontinuous phase.